Machining conditions, oscillating conditions, and the like of an electrical discharge machine are determined according to the shape of a tool electrode and electrical discharge energy during machining. For example, machining conditions corresponding to high energy are used for rough machining and those corresponding to low energy are used for finish machining. Under the low-energy machining conditions, a machining area is restricted due to problems of electrical discharge gap control and electrical discharge dispersibility, and it is commonly known that finish machining performance reduces as the machining area increases.
To solve these problems, a technique that enables to supply metal powder to a machining gap is proposed in Patent Literature 1, for example. The metal powder is supplied to the machining gap to disperse electrical discharge points, thereby improving machining stability and improving the reduction in the finish machining performance even if the machining area increases.